Keeping Promises
by MrsMCrieff
Summary: This is a short two part Sherlolly which is part modern times and part TeenLock! Based on a prompt from mychakk. Rated M for smut.
1. Chapter 1

**So this story came about as a prompt from mychakk** **who wanted a story about Sherlock and Molly making a pact to have sex when they were younger. I hope I have done the prompt justice. So mychakk this is dedicated to you!**

**It will be a tale of two halves, literally and figuratively. Two chapters but also it flicks between modern day and Molly's memories from 15 through to 18. I didn't want big chunks of the story italicised so I hope it is obvious where the times change.**

**I still own none of the characters but am eternally grateful that I am able to play with them.**

**Chapter 1**

Today was Molly's 33rd birthday and bar a phone call from her mum and a joint card from her colleagues at work there was no one who really cared. Molly sat down heavily on the settee with a glass of wine and pondered where it had all gone wrong. She had hoped to be married by now, to have kids or at least have plans to have kids. Instead all she had was her job and a small, ginger cat.

She sipped on her drink and found herself remembering back to when she was fifteen, it seemed like a lifetime ago. She had been awkward, quiet and shy, the class swot; she had never really had many friends which was why it was strange that her best friend was her complete opposite. He was rebellious, quick witted with a cutting tongue but above all he was a genius. A straight A student already earmarked for Cambridge or Oxford, which was why he got away with playing truant from school so much.

Back then he was known by his first name, William, or Will as he preferred to be called. He just seemed to latch onto Molly. More often than not when she left the library, having finished off whatever homework she'd been set, he would be waiting for her; leaning on the library wall smoking a cigarette or drinking a bottle of beer.

He'd walk her back to her place and, given her dad's long hours working as a plumber and her mum's complete indifference, they'd go up to Molly's room and listen to music or chat about anything that took their interest. Unlike most teenage chat it was normally science based or medical. Molly was already keen on becoming a doctor and Will was thinking, on the advice of his parents, about pursuing a career in Chemistry though he was ambivalent at best.

It only took Molly one week into this weird friendship to fall madly in love with Will. At first she hoped and prayed he would ask her out but as the weeks progressed into months she began to realise that would never happen. He didn't just show no interest in her he showed no interest in anyone, not sexually.

It was about eight months into their friendship and just before her sixteenth birthday when IT happened.

It was a warm summer's day and Molly had been enjoying sitting on a rug in the park doing her homework when the other girls had found her. They were all from Molly's class, all popular, all with older boyfriends, normally from the year above at school. They regularly mocked Molly for being mousy, ugly, geeky and today was no different. They laughed at her, at her clothes, at the fact she'd never had a boyfriend and most likely never would. She'd grow old and alone and die with hundreds of cats, that one set them off into helpless giggles.

They all knew about her friendship with Will but they also knew he'd never shown her any interest. With hindsight Molly realised they were probably jealous of her friendship with him, he was the best looking guy in the whole school. They'd all made a play for him at one time or another and been knocked back, some more cruelly than others, but at the time Molly didn't see this she just took their barbs and laughter and tried not to let them see her cry.

They walked away as Will appeared on the other side of the park heading towards where Molly was sat. He threw himself down on the rug and started to light a fag.

'Hi, how are you?' He suddenly noticed her distress and sat up straighter his eyes narrowing, 'Hey, what's up? No hang on don't tell me I want to see if I can work it out.'

Molly rolled her eyes, this was Will's new game. Trying to work out things about people from subtle clues. He had been rubbish at first but Molly had to admit his guesses were getting more accurate nowadays.

He sat and looked her up and down, he took in her slightly red rimmed eyes, the girls from their school sitting not that far always casting occasional glances over at them before giggling and gossiping to each other.

'What did they say to you Molly?' He scowled in their direction but was just rewarded with more giggles.

'Nothing, it doesn't matter.'

'Yes it does. Come on tell me. We're mates aren't we?'

'It was nothing that wasn't true, they just didn't really have to rub it in.'

'Just tell me, I'm getting bored here.'

Molly sighed, knowing how quick Will was to boredom, 'they were just laughing at the fact that I've never been kissed, that I haven't got a boyfriend and I haven't had sex.'

She stared at him sullenly as though daring him to contradict it, 'see nothing that isn't true, I mean look at me Will, I don't look like them, I don't dress like them. Who's ever going to want me?'

Will frowned again, he hated emotions and feelings, they were too complicated and messy. 'Oh just ignore them. I've not had sex either and neither have most of them, they just pretend they've done it so they look good in front of their mates.'

'Yeah, well. At least they'll get a chance to have sex. I'll probably die a virgin.' Molly was in a full on sulk by now and it made Will laugh.

'I tell you what then Molly. If you haven't had sex by the time you're 18 I'll sleep with you. That way we can both go off to Uni as non-virgins.'

'Haha very funny Will. Are you taking the mickey of me as well? I thought you were my friend.'

'I am and I mean it. Tell you what, I'll prove my commitment to the promise. Close your eyes.'

'I'm sorry...what!'

'Come on Molls, close your eyes.'

Molly sighed once more but did as he asked. A quick glance told Will they were still being observed so he leant forward and catching the back of Molly's head he pulled her too him and kissed her.

Molly hadn't been expecting this at all. She felt Will pull her towards him and then his lips were on hers. His mouth was warm and he tasted of cigarettes but his lips were soft as they moved against hers. She thought her heart was going to explode, she felt dizzy and knew she was holding onto his t shirt for dear life.

It only lasted a minute or so but it wasn't long enough for Molly. When he pulled back she opened her eyes feeling dazed and unsure. Will was smirking at her and saying something, 'there you go Molls, a kiss to seal my promise and proof for those cows sitting over there that you have been kissed. They'll also assume I am your boyfriend now so that's two birds killed with one stone. Anyway enough of this my dog, Redbeard, has an abscess, it's so cool. Maybe we could get some puss from it and use one of the school microscopes to analyse it whaddya think?'

Molly nodded her head in agreement and listened to Will prattling on about the different experiments they could conduct but her head was firmly fixated on that kiss. Her first kiss. It just made her want more, want him more.

He never mentioned it again and six months later he and his family moved away. Apparently his brother Mike was finishing university and had got a job in London, in the civil service or something. Anyway given that Will was expected to go to Oxford in a couple of years his parents had decided to move to a village in between London and Oxford so they could all keep in touch better.

Molly had cried for a week after he had gone, not just because she had fancied him but because he was her friend, almost her only friend.

They'd kept in touch initially, although it was quite sporadic from Will. He'd send her interesting articles that he'd found or photographs, often of dead animals, that he'd come across, describing his he'd figured out their cause of death. His morbid interests made her smile, which was probably why they'd become friends in the first place.

After a year though it had pretty much dried up. This had not been a world connected by computers and social media, they'd only had telephones and letters to keep them connected. Molly had kept every single note and article and photo in a box under her bed.

On her eighteenth birthday she'd fleetingly wondered if she would hear from him, if he would keep his promise (after all she was still a virgin) but she'd heard nothing.

A week later her parents went on holiday for the first time in five years. Molly hadn't wanted to go with them, it had sounded really dull, so she was home alone and looking forward to maybe having some friends round for a girly chat and a sleepover.

The first night her two best friends Meena and Sarah had come over bringing with them a cheap bottle of cider. They'd found some glasses and sat around drinking and playing truth or dare, though the truths weren't very risqué and the dares were a bit tame. It was fun never the less and ended up deteriorating into a general chat about the boys in school they fancied and their chances or not of going out with them. Molly was surprised then when the doorbell rang just before ten o'clock.

She opened it to find Will stood on her doorstep holding up a twelve pack of Durex, 'hey Molly, you didn't think I'd forget did you?'

Molly stood there in shock for a moment before she realised a teenage guy was stood outside her parent's house holding up condoms, 'Oh my God, get inside before the neighbours see you, they do know my mum and dad you know!' She pulled his arm down that was holding the box and used it to pull him through the door.

'What the hell are you doing here?'

Will's face fell, 'well I had hoped for a more enthusiastic response. I travelled a long way to get here.'

Molly looked past him at the slightly beat up motorbike that was parked where her parent's car normally sat, 'is that yours?'

Will looked proud, 'yup. My parents got it for me as a bribe to make sure I passed the Oxford entry exams. I'm off to Balliol College in October to study Chemistry, well for as long as I can stand it anyway. You?'

Molly smiled, 'York, I'm doing medicine.'

'Doctor Molly Hooper, it has a nice ring to it.'

'I can't believe you're actually here. I missed you.' Molly tentatively moved forward and put her arms around him. It took a moment but he slowly brought his arms up to hug her back briefly. 'Come and meet my friends...do you want a drink?'

'God do I have to, can't you just get rid of them.'

'No I can't. Come on...please.'

He grumpily followed behind her and sullenly sat on the settee drinking the insipid cider until her friends got the hint and left. They remembered all about Will and Molly's massive crush on him, they weren't about to rain on her parade by forcing her to go through with their sleepover. They gathered up their things and made their way out giggling their goodbyes to Will and mouthing Good Luck to Molly. At the door they made her promise to ring them as soon as he'd gone to let them know EVERYTHING.

Molly shushed them, 'he can hear you know,' but promised none the less.

By the time she got back to the front room Will had found her father's whisky and poured them two glasses. 'Here you go, you shouldn't drink cheap booze Molly it's disgusting.'

'And you shouldn't drink my dads whisky, it's expensive. How on earth am I going to replace it?'

'Oh don't stress, I'll get you another bottle if you need it. Now come on drink, we need to be more relaxed if we're going to have sex.'

Molly literally choked on her drink, to the point that Will wondered if he'd have to hit her on her back. 'You can't be serious about that. It was years ago when we made that promise, we were just kids.'

'So. You're still a virgin, I'm still virgin. I know you like me so the question is more why not?'

Molly sat sipping the whisky trying to think of a good reason why not. She liked him, she really liked him, she always had and the thought of losing her virginity with him felt safe and comfortable. Plus chances were this would be the last time she'd ever see him. It was unlikely their paths would cross in the future. She didn't want to look back on this as a lost opportunity, a regret. It also helped that the whisky was making her feel warm and fuzzy.

'OK.'

'Great,' he immediately put his empty glass down and came and sat on the floor opposite her. Molly gulped nervously, biting her lip.

Slowly he put up his hand and used his finger to pull her lip out from between her teeth. She watched him as he did, noticing his pupils were dilated, his breathing seemed as erratic as hers. It helped knowing that he was as nervous as she was, it gave her the confidence to move forward and hold his face before kissing him.

**Am I mean ending it there? I hope you're all enjoying it so far. The final half will be posted in a couple of days so until then fill your time with reviews and follows and favourites. Go on you know you want to.**


	2. Chapter 2

**So glad you all like this, especially that mychakk approves. Without further ado here is part two, I hope its meets the expectations following part one.**

**Chapter 2**

Molly poured herself a second glass of wine and scratched behind Toby's ear. He always seemed to sense when she was a bit down, he gave a deep satisfied purr and pushed his head into her hand. Molly wasn't too worried about wallowing in her memories, her bleak moods never lasted for long, she had always naturally seen the bright side of life was able to stay positive. She smiled to herself as she thought back to her first time all those years ago. She knew exactly why those memories were flooding back tonight.

'Oh Tobes, you should have seen our first time. We were pretty awful.' She chuckled ruefully.

They had spent about twenty minutes just kissing before Molly asked whether they should go up to her bedroom. Will had just nodded and picked up the condoms, discretely shoving them into his pocket. Molly caught him doing it though and blushed at the thought of what they were planning to do. Was she really going to go through with this?

Her doubts vanished though when they got to her room, the walls of which were still covered in posters of her favourite bands taken from her copies of Smash Hits. Will pushed her back onto the bed that they'd sat on as friends so many times before. He half lay on top of her and kissed her once more letting his tongue explore her mouth. This time he tasted of whisky and she could feel a nervous kind of energy starting to run through her body at the feel of his weight lying on her. It made her want more of him.

She let her hands slide under his t shirt and up and over his back. His skin felt warm and she could feel his muscles twitching and flexing as her hands moved across him, he groaned into her mouth when she used her nails to scrape over his skin.

He quickly knelt up and pulled his t shirt off before kicking off his shoes and socks. She leant up on her elbows watching him and wondering if she were brave enough to remove some of her own clothes. In the end she let the whisky do the talking and she sat up pulling off her own top, trying not to listen to the scream of embarrassment in her brain. She hadn't bothered to put a bra on that day so she knew she was now sat half naked in front of him. She had never in her life felt so exposed, she could feel her shoulders hunching over in a bid to hide herself from him.

When he didn't say or do anything she tentatively opened her eyes to find him staring at her with his mouth forming a silent Oh. His eyes flicked nervously up to hers before going back to her chest. She saw him lick his lips before uncertainly bringing his hand up to cover her right breast. He squeezed gently and she found herself pushing into his grip. It seemed to give him to confidence to slide his thumb across her nipple.

She closed her eyes and felt him push her onto her back again. It was then that she felt his mouth on her, sucking her nipple in, feeling his tongue swirling round. She caught at his head, her hands twisting into his black curls and she moaned at the sensation. It felt like nothing she had ever experienced before. Her reaction seemed to excite him further and she felt him fumbling with her jeans trying to undo them as he pushed himself against her.

She could feel something hard against her thigh and she wondered if it was his erection. She'd read all about reproduction of course, she was hoping to study medicine after all, she'd even seen photos which her and her friends had giggled over but she'd never actually seen or felt one in real life.

She awkwardly helped him shimmy her jeans off and then watched shyly as he took off his own trousers. She couldn't help but look down at him, her eyes widening at the reality of seeing him hard and ready for her. He fished out the condoms and sat back down with them, looking over at her apprehensively. She watched as he took one out and put it on and she wondered briefly whether it would hurt but then he smiled and leant forward to kiss her again and her fears diminished.

She had loved Will for so long and whether he was here for one night or for longer she was determined to make the most if it. She lay back again taking him with her feeling his weight on her once more and it just felt right. He was her friend and she knew he would be gentle and thoughtful.

She helped him to position himself at her entrance and they watched each other's expressions as he slowly pushed into her. It felt strange to Molly, he felt so big, she could feel him stretching her walls, it was a little painful but not too bad. She gasped and looked up at him and thought to herself that she had never seen him looking more open and vulnerable. 'Are you OK?' He asked once he was fully inside her. His voice trembled slightly betraying his own feelings. She nodded and brought her hand up to his face and as he moved against her they kissed once more.

His head soon dropped to her shoulder as he started to slowly thrust in and out of her, she could hear him muttering her name, telling her how good she felt and she closed her eyes, her hands trailing over his back holding him to her. She was starting to get used to the feel of him, his movements setting off shockwaves in her body and she moved with him trying to match his pace. She felt as though she were building towards something, wanting something but she wasn't quite sure what, she just knew she wanted him to carry on. It was at that exact moment that he thrust into her more deeply and groaned loudly before he sagged back onto her. It was all over.

He kissed her briefly before moving to lie at her side breathing heavily. Molly watched him lying there with a small smile playing on his face but she felt strangely unsatisfied. Was that it? She wondered what the big deal was and why people seemed so keen to 'do it'.

Will opened his eyes and saw her watching him. He lifted his hand and stroked her cheek, 'are you alright? Did I hurt you?'

'No, I'm fine. How about you?'

'Mmm yeah I'm good.'

Molly bit her lip, 'so is that it, are you going back home now?'

He leant up on one elbow looking down on her, 'well...only if you want me too. I had planned on staying longer, after all that was just our first time and I don't think you came. I have 11 more condoms and plan to discover at least five different ways of making you orgasm before I go home. You up for that?'

Molly blushed but giggled at his forwardness, she'd read about orgasms and it definitely didn't feel as though she'd had anything like that. She couldn't quite believe she felt so comfortable around Will naked and talking about sex but he'd always been brutally honest and she'd missed it, she'd missed him. 'You can stay as long as you like...well, until my parents are due back anyway.'

MHMHMHMHMHMHMHMHMHMH

Molly sat back with her wine, Toby curled up asleep beside her. She found herself telling her cat all about that week with Will, 'we certainly got a bit better at sex by the end and yes he did make me come more than once, God he was good by the end.' She said wistfully.

She fell back into a thoughtful silence remembering their good byes to each other. It wasn't a sappy or romantic goodbye, that was never his style.

'Good Luck Molly Hooper, I reckon fifteen years from now you'll be working in a hospital saving lives with a husband and a pack of kids.'

She laughed remembering their conversation from a few nights before, 'and you William Holmes will be a famous chemist probably winning a Nobel Peace Prize with a girl on every continent.'

He smiled briefly not quite catching her eye before he bent forward and kissed her cheek, 'goodbye Molly.' Then he'd turned and slung his rucksack over his back before picking up his motorbike helmet.

She wished she'd got a photo of him or something before he'd left but they'd been so caught up in each other she hadn't thought to take any. She waved as he buzzed away from her house on his little 250cc death machine. She had no regrets about what they had done but she couldn't quite believe that she'd never see him again.

She was right on that last part, it had been ten years and what felt like a lifetime but there he was large as life in her morgue introducing himself as Sherlock Holmes, all reinvented with a made up job title to boot.

She knew he recognised her, she saw his eyes widen and his stride falter as Mike walked him over and introduced them but he never once said anything and she respected his decision. If he wanted to be someone new and not acknowledge his past she wasn't going to force the issue. She tried to reignite things between them, asking him out to coffee, mentioning an exhibition he would be interested in but he rebuffed her each time and eventually she'd let it go. It didn't stop her feelings for him coming back in full force though.

In truth they had never gone away, they had always been there, a memory, a fantasy in the back of her mind. A template to compare all other men too, always sad when they fell short by miles.

She eventually told him about her father's death, knew he would quickly work out that that was why she had changed her course and gone into pathology.

And of course she wasn't surprised when he came to her for help the night he'd thought his life was in danger. Who else would he trust but his friend Molly, she had always been there for him and he'd always trusted her.

They had an easy friendship now, Molly had long since given up any thoughts of being with him, or with anyone really. After the aborted engagement with Tom she suspected those girls from the park would be right in the end. She would grow old alone and die with lots of cats, maybe she should get Toby a friend, or even a girlfriend and hope for kittens in the future.

MHMHMHMHMHMHMHMHMHMH

A couple of days later and Molly was coming out of her maudlin birthday mood just as she had anticipated she wpuld. It helped that they were experiencing a bit of a late summer so she was enjoying walking to work and back making the most of the sun.

Sherlock and John had been away on a case for the last week so it was a shock when she got home on the Friday evening to find him lounging against her door.

'Oh, hi Sherlock. Is the case over then?'

'Yes, Graham has taken over now, we won't be needed again until the trial. I hate trials, always so tedious.'

She smiled widely, 'and always a chance you'll end up in the cells for contempt of court.'

'Yes, that too.' He followed her into her flat and she was bemused when he took off his coat and hung it up on the coat peg in the hallway.

'Coffee?' She asked as she made her way into the kitchen.

'Yes, thank you Molly.'

She set it all going and then turned to face him, 'so, how can I help? It's not like you to visit me at home. At least not without something life or death going on.' As she said the words she had a sudden thought and felt her stomach turn over. She pushed herself away from the kitchen cabinet where she'd been leaning. Before she even managed to get another word out he held up his hand smiling, 'I'm fine Molly, nothing like that.'

He paused and looked a bit unsure of himself making Molly wonder what on earth was going on, he was normally so confident.

'What is it Sherlock? What do you need?'

He seemed to pull himself together and looked at her with a shy smile that she swore she hadn't seen in fifteen years, 'you, Molly. I need you.'

He fished in his pocket and brought out a small, black velvet box. He opened it and held it out to her. Inside was an engagement ring with three diamonds in a row. It was perfect.

She looked up at him thoroughly confused, 'I'm sorry, I don't understand. Is there some joke I'm not getting?'

He stepped closer to her, 'I know I'm a couple of days late on our promise but I was a couple of days late last time and you let me off.'

Realisation started to sink in with Molly, the memory of that last pact all those years ago rearing its head. Will...Sherlock lying in her bed after he'd made her come twice in a row looking at her, his grin wide and proud, and promising that if she were still single in fifteen years he'd marry her. She'd laughed at him looking so serious and nodded her head in agreement, never for one moment believing he'd keep it.

She knew she must look like a goldfish, her mouth moving but no words coming out, 'but...but, hang on. You've never mentioned this...at all! Never even referred to us being friends or..or that week we had together. You know you don't have to uphold that promise now, I never expected you to.'

'I know, but I want to. I've always wanted to, that's why I made that promise in the first place, because for me it's only ever been you Molly.'

'But why have you never said anything, done anything about it? I don't understand. You've had years to say something.'

He huffed once, 'I'm not a good man, Molly, and I'm sure I'll be an even worse husband. I had to give you every chance to find someone better. That's why I held back over these last five years, watching you dating loser after loser, with the odd psychopath thrown in for good measure.' He smirked quickly before his face became serious again. 'I thought maybe you'd found someone better, someone right for you when I came back last year and you were engaged. Then I met him and I knew there was no way you would marry him. And now here we are, both 33, both single...'

Molly's face was conflicted, here was the man of her dreams, literally, standing in front of her offering to marry her but she wanted more, needed more.

'I don't want to be a wife in name only Sherlock. I want a marriage; I want love, maybe even kids.'

He didn't even hesitate he just picked up her left hand and slid the engagement ring onto her third finger as she watched biting her lip with nerves.

He looked down on her and she suddenly realised how close he was. She could see the freckles on his cheeks, the pulse in his neck; feel his breath on her face, 'I want that too. I love you Molly, I always have and I always will. My biggest regret was not telling you all those years ago before I left your house. Now will you marry me?'

Molly had barely finished saying yes when he kissed her. The memories of him kissing her all those years again came flooding back like a visceral memory of him left imprinted on her body. They moved together perfectly and Molly was left breathless by the pent up passion shown in that one, long, searing kiss.

'God I've missed this, missed you...' He kissed her again and she found herself pulling at his clothes desperate to feel his skin against hers. She didn't care that this was so new, it was as though the fifteen years just fell away and they were back in her old bedroom in her parents' house.

By the time he pulled away, his jacket was on the floor, his shirt was open and half out of his pants and he was pulling her shirt over her head. He promptly threw that onto the floor as well quickly followed by her bra. Then she was being sat on the kitchen side whilst he covered her breasts with his mouth and hands.

'I wonder,' he said slyly in between kisses and sucks of her nipple, 'if I can still make you come five different ways, I'm sure there are more I can learn now.'

She giggled as he went back to work before gasping loudly as he bit down just enough that she balanced between pleasure and pain, 'oh God, Sherlock, don't stop.'

Five minutes later she'd already had one orgasm and he was positioned between her legs, 'are you sure?' He asked. She just nodded, holding onto him as he pushed into her. Just as it had all those years before he felt so right, he seemed to fit with her as though they were matching jigsaw pieces. His technique was certainly a little more mature and polished but he was still her Will.

Part of her wondered whether they shouldn't have at least been able to make it into the bedroom but then she decided she didn't care, there would be plenty of time to have sex in every room in her flat if they wanted to, and boy did she want to.

She could feel her second orgasm building quickly and knew that he knew it too. He seemed to know instinctively what pace to set and how to angle himself for maximum effect. God, a mind palace could be a wonderful thing, he hadn't deleted a thing about their time together.

She came crying out his name, her hands scrabbling for purchase on his naked back and a moment or two later she felt his come streaming inside her.

'Mmm, you have no idea, Molly, how good that felt! I promise you, I will never let you go again.'

She smiled and kissed his shoulder, 'now that's a promise I'm going to make sure you keep.'

**And there we have it. I hope you enjoyed it though maybe not as much as they did ;). **

**Let me know what you thought, you know I always like hearing from my readers.**


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